Do my filled PDFs leave my browser?

No. The free fill flow runs entirely client-side via pdf.js for rendering and pdf-lib for the actual edits — there is no upload step in the code path. Verify by opening your browser's DevTools Network tab while you edit; you will see zero outbound requests carrying your PDF.

Can I fill a scanned PDF?

Not in the free tier — scanned PDFs need OCR to detect where the fields are, and OCR needs server compute that your browser does not have. The v1.1 paid tier ($1.99/document) handles scanned forms via cloud OCR with a 60-second TTL. AcroForm-enabled PDFs (the kind banks and governments publish) work for free today.

Does Vietnamese text export correctly?

Yes. Standard PDF fonts (Helvetica/Times/Courier) only cover ASCII, but the export pipeline auto-fetches Roboto-Vietnamese with full Unicode diacritic coverage the moment an annotation contains a non-ASCII character. "Nguyễn Thị Hằng" renders identically in the editor preview and in the downloaded PDF.

Can I fill the same PDF on a different device?

Sessions autosave to your browser's IndexedDB and are restorable via the /app?s=… URL — copy or bookmark that URL on one device and paste it on another to pick up where you left off. The token in the URL is the only thing pointing at your work; nothing about the session lives on our infrastructure.

Do my files leave my browser?

No — at all, today. All editing runs client-side via pdf.js and pdf-lib. The v1.1 paid tier will add opt-in cloud OCR / unlock; even then files are deleted within 60 seconds.

Yes. Everything in the editor today (annotations, AcroForm fill, watermark, page numbers, split, merge, export) is free forever. Paid tier ($1.99/document) covers cloud OCR + AI autofill on scanned PDFs in v1.1.

How do I keep my work between sessions?

Edits autosave to your browser's IndexedDB every 500 ms. The editor URL becomes /app?s=… — copy or bookmark to return. Sessions live entirely on your device.

Can I use this for sensitive documents — tax, medical, legal?

Yes — that's the point of client-side execution. Your tax return, medical record, or legal contract literally never touches our infrastructure. Verify in DevTools' Network tab.

Does Vietnamese text export correctly?

Yes. The export pipeline auto-fetches Roboto-Vietnamese (with full diacritic coverage) when any annotation contains non-ASCII text.

Fill PDF Form

Fill any PDF form online in your browser. Free.

Drop your PDF, type into the fields, sign, download. AcroForm-fill is free forever and runs entirely on your device — your file never touches a server.

Drop your PDF here

or click to browse · 10 MB max free · stays in your browser

Open the free editor How it works

Files never leave your browserNo signup requiredWorks on AcroForm PDFs · password-protected (paid)

FREE TIER

$0 forever

AcroForm autofill, sign, export · client-side, no upload

Open editor

FOR FLAT SCANS · v1.1

$1.99 / document

OCR + AI autofill + 24h edit window · ships with v1.1

See pricing

The full guide

Everything you need to know about filling PDF forms online.

What is a PDF form filler?

A PDF form filler lets you type into the blanks on a PDF without installing Adobe Acrobat or any desktop software. PDFCatalyst handles two kinds: AcroForm PDFs, where the form fields are real interactive fields the document author defined, and flat PDFs, where the form is just printed text and lines that the author never wired up. The free tier handles AcroForm fills entirely in your browser; flat-PDF autofill via OCR ships with the v1.1 paid tier.

How to fill a PDF form online for free

Drop the PDF onto the editor at /app — or click to browse. If it's an AcroForm — the kind banks, governments, and HR departments usually publish — every field is instantly clickable. Click, type, tab to the next, sign with your finger or stylus, and download. There is no signup, no email wall, no per-document watermark. The file is parsed and edited entirely in JavaScript inside your tab using Mozilla's pdf.js for rendering and pdf-lib for the byte-level edits, so we cannot leak what we never receive.

Vietnamese forms (CCCD, tax, BHXH, visa)

PDFCatalyst is built Vietnamese-first. The export pipeline auto-fetches Roboto-Vietnamese with full diacritic coverage the moment any annotation contains non-ASCII text, so "Nguyễn Thị Hằng" or "Trường Đại học" renders identically in the editor preview and in the downloaded PDF — no mojibake, no missing tone marks. The structured-address handling is aware of phường, quận, and tỉnh; most generic PDF tools collapse a Vietnamese address into one line and lose the structure on export.

Privacy: where do my files go?

Free-tier filling is 100% client-side. The PDF is parsed, edited, and re-exported entirely in your browser via pdf.js + pdf-lib — no upload, no temporary server cache, no log line saying "user X edited document Y". Verify it yourself: open your browser's DevTools, switch to the Network tab, and edit a form. You will see zero outbound requests carrying your PDF. The v1.1 paid tier adds opt-in cloud OCR for scanned PDFs, with explicit per-document consent, a 60-second TTL, and Singapore-region processing. The free fill flow stays browser-only forever.

When to upgrade to AI autofill

If your form is a scanned page, an image-only PDF, or a multi-language layout where labels and blanks aren't aligned predictably, the v1.1 paid tier ($1.99/document) covers cloud OCR plus AI-assisted field detection that reads field labels and matches them against your saved profile. Includes 30 OCR pages and 30 AI-detected fields per document; overages are quoted before charging — never silently. Until v1.1 ships, the free tier still handles every AcroForm-enabled PDF, which is the format almost all modern government and bank forms ship in.

Long-tail use cases — beyond filling text

Most "fill PDF online" searches end at typing in fields, but real workflows usually need a couple more steps. After filling a contract, drop your signature with the PDF signature tool. Add a notarised stamp or company logo via add image to PDF. Stamping `DRAFT` across every page before circulating internally? Use the PDF watermark tool. Black out the salary line on a filled offer letter before forwarding it to a candidate's referee with the redact PDF tool. PDFCatalyst is one editor for the whole flow — no jumping between tabs.

Fill, then assemble: combining filled PDFs

A common pattern after filling: bundle the filled form with supporting documents into a single submission file. Use merge PDF to append a CCCD scan, a residency certificate, and the filled form into one upload-ready file — drag-reorder the page thumbnails so the form is page 1. Or the reverse: pull just the filled-form pages out of a long source PDF (cover letter + form + appendices) using the split PDF tool before sending. All three operations run client-side, so even when you bundle three sensitive documents into one, none of them touch our servers.

How it works

Fill PDF Form in 4 steps.

01
Open the editor
Drop your PDF onto the editor at /app or click to browse from your device.
02
Type your answers
Click any field on the page and type. AcroForm fields are auto-detected and tab-navigable.
03
Sign the form
Open the signature pad, draw or upload your signature, and place it anywhere on the page.
04
Download
Click Download to save the filled PDF. Your file never leaves your browser.

Frequently asked questions

Questions about this tool.

Yes. AcroForm form filling, signing, and exporting are free forever in PDFCatalyst — no signup, no card, no per-document watermark. Cloud OCR and AI autofill on scanned PDFs cost $1.99/document when v1.1 ships, but the free flow handles every form that has real interactive fields (which is almost every modern bank, government, and HR form).

Fill your form in your browser. Free.

No signup, no upload, no watermark. AcroForm fills run entirely on your device — your file never touches a server.

Open the free editor